Field of the Invention
The invention relates to a thermally insulated housing with a substantially vacuum tight outer shell and an at least substantially vacuum tight inner enclosure that is spaced apart therefrom. The elements are connected to one another in a vacuum tight fashion by a connection section that is at least approximately U-shaped in cross section. The connection section is secured by its section limbs to the outer shell on the one hand and to the inner enclosure on the other, and which encloses, t together with the outer shell and the inner enclosure, an evacuated intermediate space which is filled with a thermal insulation material.
Thermally insulated walls that are based on vacuum insulation technology are currently formed virtually without exception from two metallic sleeve walls which are disposed at a distance from one another and which are supported on one another by a supporting material which can be evacuated. The walls are welded along their contour to a connection section configured with a U-shaped cross section in order to enclose a space that can be evacuated. During the implementation of the welded connection it is necessary to ensure that the connection section, which has to be made as thin-walled as possible in order to avoid thermal conduction which considerably reduces the insulation capacity of the thermally insulating wall, does not have a tendency, as a result of the supply of heat during the welding process, to distort, which may under certain circumstances lead to leaks. Attempts are made to avoid this with a complicated clamping technology, which additionally involves the problem of accommodating the necessary clamping mechanism on the available restricted space. In order to avoid both the costly clamping mechanism and the distortions, a procedure has been adopted which provides that all sides of the connection section have a thickness of material that is in the order of magnitude of the sleeve shell. However, the result of this is that even more cost-intensive supporting materials, such as glass fibers, for example, have to be used to support the two sleeve walls so as to avoid a flow of heat which reduces the insulation effect of the thermally insulated wall. The supporting materials have the additional property of a high relative density leading to a high intrinsic weight.